mindfulness meditation is great for learning to take your thoughts less seriously and become internally validated (core confidence) instead of looking externally for reasons to feel good (situational confidence).
This is important. To see the thoughts for what they are - just thoughts. You are not a thought, and the person you think you are does not exist - it's just a concept made out of memories and fantasies.
I spent a lot of time and energy trying to improve and change myself. I wasn't really happy with with myself. However the biggest change occurred with the loss of everything I thought I was - ego death during a trip on ayahuasca.
I realized that the core of who I am can't be found in the personality or in the thoughts. I am not any of these temporary phenomena; I am actually the awareness of everything. Thoughts and emotions are just like passing clouds - I'm not a cloud but the changeless sky.
This realization brings peace to the mind. I don't have perfect confidence in my social skills or in my intellect, but I have absolute confidence in who I am.